WASHINGTON (AP) - Authorities say a man who was charged in connection with the death of a D.C. school principal has been killed during a robbery attempt.

Police say 21-year-old Joel Johnson died Wednesday in the 4200 block of First Street in southeast Washington. Police say Johnson and another man were armed when they tried to rob a couple in their apartment. Authorities say a struggle ensued and Johnson was shot.

Johnson had played a role in the killing of junior high school principal Brian K. Betts two years ago in Silver Spring. He had taken a deal and pleaded guilty to a lesser charge. The Montgomery County State's Attorney's Office says Johnson was sentenced to five years in prison with all but 18 months suspended and was freed in April 2011.